In order to more effectively produce hydrocarbons from downhole formations, and especially in formations with low porosity and/or low permeability, induced fracturing (called “frac operations”, “hydraulic fracturing”, or simply “fracing”) of the hydrocarbon-bearing formations has been a commonly used technique. In a typical frac operation, fluids are pumped downhole under high pressure, causing the formations to fracture around the borehole, creating high permeability conduits that promote the flow of the hydrocarbons into the borehole. These frac operations can be conducted in horizontal and deviated, as well as vertical, boreholes, and in either uncased wells, or in cased wells through perforations. The frac operations can be conducted in intervals, also called stages or “clusters,” where each stage or cluster contains multiple perforations.
Chemical diverters are often times utilized in frac operations. These diverters can aid in diverting fluid to each frac cluster so that each cluster receives its proportional share of fluid and proppant during the frac operation. Diverter materials can include materials such as particulates, polymers, or viscosified fluids that can form a fluid impermeable plug in a selected perforation. The diverter “plugs” an open perforation to create excess pressure throughout the interior volume of the casing. This excess pressure acts to open other, un-plugged perforations to divert frac-fluids into the now open perforations. Currently, there is no method of knowing which clusters in a stage have been plugged and which perforation clusters are capable of or incapable of being open with diversion.
Therefore, a need exists for methods for determining which perforation clusters are plugged, open and not plugged, or closed and not plugged. There is a need for methods for identifying chemical diverter material placed in a borehole region and a need for chemical diverter material.